This disclosure generally relates to an electronic control unit-mounting electric junction box used for vehicles and the like, and more particularly, to an attachment structure of an electronic control unit.
Electric junction boxes, such as fuse boxes, relay boxes, and junction boxes, have been used for electric wiring of vehicles. An electric junction box generally has a conducting path in a casing formed of a lower case and an upper case, and is configured to electrically connect circuits and electronic parts of an electronic control unit to respective external wires via the conducting path in a junction box main body.
Incidentally, electric junction boxes are largely classified into two types: (1) an external type having an electronic control unit attached to the outside of the upper case as is disclosed in, for example, JP-A-10-174253, and (2) a built-in type having an electronic control unit attached to the inside of the upper case as disclosed in, for example, JP-A-2002-58134.
For example, regarding a printed-wiring board forming the electronic control unit, when electronic control units are prepared to specifications at a particular place of destination, such as types and grades of vehicles, there are some cases where it is also preferable to prepare respective printed-wiring boards at the place of destination. In particular, because automobiles for oversea use have specifications that vary from country to country, such as horsepower control, fuel consumption control, and emission control, electronic control units manufactured by local manufacturers in the respective countries may be attached in some cases.
It is desirable to also manufacture the electric junction boxes at the same place of destination as that of the electronic control units. However, considering the characteristics of a standardized circuit, it is advantageous to centralize the manufacturing at one place in terms of cost, such as facility investment. Electric junction boxes and electronic control units are therefore manufactured at different places in some cases and when electric junction boxes and electronic control units are put together, it becomes necessary to transport one of the former and latter parts to the place of manufacture of the other. Hence, when electronic control units are transported to the place of manufacture of electric junction boxes, printed-wiring boards having mounted electronic parts are contained in special cases to safeguard the printed-wiring boards against impact and the like during transportation. Further, so that a worker at the place of manufacture of electric junction boxes is able to easily attach the printed-wiring board while the printed-wiring board is contained in the special case, a connector section to be connected to the electric junction box is provided to the case. Conversely, in a case where electric junction boxes are transported to the place of manufacture of electronic control units, work man-hours are increased by removing the casing of an electric junction box and then connecting the printed-wiring board of the electronic control unit to the conducting path. It is therefore preferable to use an electric junction box of the type having an external electronic control unit when the place of manufacture of electric junction boxes is different from the place where electronic control units are attached.
In contrast, when electric junction boxes and electronic control units can be prepared and assembled at the same location, there is no need to transport the electronic control units from one place to another, and it is no longer necessary to contain the printed-wiring boards in the special cases. Accordingly, allowing the printed-wiring board to be contained between the lower case and the upper case, and connecting the printed-wiring board to the conducting path in the electric junction box without mediation of the special case can reduce the number of parts. Further, connectors become unnecessary as a result of the soldering the conducting path to the printed-wiring board. Thus, the number of parts can be further reduced. In such a case, it is preferable to use electric junction boxes of the type having a built-in electronic control unit.
However, when electric junction boxes attached with electronic control units are manufactured, it is preferable to complete an electronic control unit-mounting electric junction box to which attachment of the electronic control unit is completed in a place close to a wire harness assembly line or a manufacturing line of an automobile manufacturer in terms of a reduction of a manufacturing tact time and a transportation charge. As a result, both the situation where the external type is suitably used because electronic control units and electric junction boxes are manufactured at different places, and the situation where the built-in type is suitably used because the former and the latter are manufactured at the same place, may coexist in some cases.
Hence, even when consideration is given to whether the location of assembly of the electric junction boxes and electronic control units is different from, or same as, the place where the electronic control units are prepared in advance, it is necessary to prepare electric junction boxes of both the external type and the built-in type in the related art, thereby resulting in an increase of the manufacturing costs and intricacy of parts management